Nu, nu&#39;-tetramethylene-bis



United States Patent 0.

3,148,216 N,N-TE'IRM/lETHYLENE-BIS(2,6-DI- METHYLANEINE) Seymour L. Shapiro, Hastings on Hudson, and Louis Freedman, Bronxville, N.Y., assignors to US. Vitamin and Pharmaceutical Corporation, New York, N.Y., a corporation of Delaware No Drawing. Filed Jan. 5, 1960, ger. No. 508 1 Claim. (Cl. 260-5705) This invention is concerned with the preparation of N,Ntetramethylene-bis(2,6-dimethylaniline), I which has the following structure:

In our co-pending patent application, Ser. No. 742,752, filed June 18, 1958, now US. Patent No. 2,993,831, issued July 25, 1961, it was disclosed that compounds of the formula: I

are potent anesthetic agents with desirable lack of toxicity. In the formula, n=35, thus including the N,N'-tetra methylenebis(2,6-dimethylaniline) which is the subject of this invention. However, it was found that the subject compound of this application could not be prepared by conventional techniques, and accordingly, a new process for the preparation of this novel compound has been made the object of this invention.

In the attempted preparation of the subject compound by reaction of 2,6-dimethylani1ine with 1,4-dibromobutane, the desired compound could not be realized by this reaction since even in the presence of an excess of the 2,6- dimethylaniline, the favored reaction was apparently that where the compound cyclized as shown in the equation below.

CH3 CH3 I H Br N N/ 2 4 H r C 3 3 For preparation of the required compound it was necessary first to prepare the N,N'-bis-succin-(2,6-dimethylanilide), II and reduce this under forcing conditions with lithium aluminum hydride. Under such conditions only partial reduction occurred, the compound isolated being the (a-[2,6-dimethylanilino]-butyr) 2,6-dimethylanilide, III. This in turn was isolated and upon treatment with lithium aluminum hydride yielded the subject compound, I. These transformations are shown in the Scheme I below.

3,148,216 Patented Sept. 8, 1964 SCHEME I R-2,6-dimethylphenyl O H H MFR CH. l R 2): (0Hm I C lNR CNR t 1'. t .1.

II III The process and compounds of this invention will be more clearly understood from a consideration of the following specific examples which are given for the purpose of illustration only and are not to be construed as limiting the scope of the invention in any Way.

Example 1 A solution of 9.3 g. (0.06 mole) of succinyl chloride in 60 ml. of ether was added gradually with stiring to a solution of 29.0 g. (0.24 mole) of 2,6-dimethylaniline in 200 ml. of ether. After the addition, stirring was continued for 40 minutes and the mixture of product and 2,6-dimethylaniline hydrochloride separated, washed with ether and then with water. The Water-insoluble product N,N'- bis(2,6 dimethylphenyl)succinamide, 24.9 g. melted at 322323 C. after recrystallization from methyl Cellosolve.

Analysis.Calcd. for C H N O C, 74.0; H, 7.5; N, 8.6. Found: C, 73.8; H, 6.9; N, 8.7.

Example 2 ('y-[2,6 dimethylanilino]-butyr) 2,6 dimethylanilide was obtained as follows: A mixture of 4.56 g. (0.12 mole) of lithium aluminum hydride in 300 ml. of ether was stirred under reflux and 13.0 g. (0.04 mole) of N,N'-bis- (2,6-dimethylphenyl) succinamide in 200 ml. of dioxane added. The reaction was maintained under reflux for 60 hours. After cautious addition of 2 ml. of water, 4.5 ml. of 40% sodium hydroxide was added and the reaction mixture stirred for 3 hours. Ether (400 ml.) was added and the residue separated and rinsed with two 300-ml. portions of ether. The combined filtrates were concentrated to about 25 ml. and on standing at 10 C., 5.9 g. (47.5%) of the product separated, M.P. 148 C., recrystallized (heptane) M.P. l49150 C.

Analysis.Calcd. for C H N O: C, 77.4; H, 8.4. Found: C, 77.5; H, 8.0.

Example 3 N,N'-tetramethylene-bis(2,6-dimethylaniline) was obtained as follows: A mixture of 1.52 g. (0.04 mole) of lithium aluminum hydride in 300 ml. of ether was treated with a slurry of 4.65 g. (0.015 mole) of ('y-[2,6-dirnethylaniline]-butyr)-2,6-dimethylanilide in 300 ml. of ether. After stirring under reflux for 30 hours and standing for an additional 90 hours, 1.0 ml. of water followed by 1.0 ml. of saturated sodium chloride and 2.25 ml. of 40% sodium hydroxide solution was added. The formed granular precipitate was separated, rinsed with ether and the combined ether filtrates concentrated. Unreacted anilide (2.4 g.) precipitated and was separated. The filtrate was evaporated to yield a residue which was distilled. There was obtained 1.11 g. (25%) of product boiling at 172- 3 182 C. (0.11 mm). On standing at room temperature the product crystallized, MP. 61-63" C., recrystallized (pentane) M.P. 72-73 C.

Analysis.Ca1cd. for C H N C, 81.0; H, 9.5; N, 9.5. Found: C, 81.1; H, 9.4; N, 9.7.

It is to be understood that it is intended to cover all changes and modifications of the examples of the invention herein chosen for the purpose of illustration which do not constitute departure from the spirit and scope of the invention.

This application is a continuation in part of our co-pending application, Serial No. 742,752, filed June 18, 1958.

We claim:

A process for the preparation of N,N'-tetramethylenebis(2,6-dimethylanilines) which comprises reacting a stoichiornetric excess of a 2,6-dimethylaniline with succinyl chloride in an inert organic solvent until formation of N,N'-bis'succin-(2,6-dimethylanilide), reacting the bisanilide with a stoichiometric excess of lithium aluminum hydride in ether-dioxane until formation of the corre- 2,653,977 Craig et al Sept. 29, 1953 2,739,981 Szabo et al Mar. 27, 1956 2,752,393 Martin June 26, 1956 2,762,845 Stroll et al. Sept. 11, 1956 2,895,991 Randall et a1 July 21, 1959 2,921,093 Shapiro et a1. Jan. 12, 1960 OTHER REFERENCES Scholtze et al.: Berichte, vol. 40, pages 852 to 858 (1907).

Sommers et a1.: Jour. Am. Chem. Soc., vol. 75, pages 5280 to 5283 (1953).

Larizza et al.: Gazzetta Chim. Ital, vol. 89, pages UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent Non 5 148, 216 September 8 1964 v Seymour L. Shapiro et a1.

It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column 1, line 60 for 1-[2,6" read sir-[me column 2, line 2 heading to SCHEME 1,, for "'R-2 o-dimethylphenyl" read R=2,6-dimethylpheny1 line 2O for "stiring" read stirring Signed and sealed this 12th day of January 1965.

(SEAL) Attest:

ERNEST W. SWIDER EDWARD J. BRENNER A'ttesting Officer Commissioner of Patents 

